Right now, version information on https://www.wikidata.org/wiki/Special:Version does not show which build of Wikibase is running. It shows 1.28.0-wmf.20 for Mediawiki, but no such information for Wikidata build or Wikibase extensions.
Moreover, Wikidata extensions do not have any links to commits - unlike other extensions - except for "Wikidata Build" extension that links to a commit from May 2014.
This makes it very hard to figure out which build of Wikidata build bundle is currently deployed. It would be nice if we could improve version display so it would be at least as clear as for Mediawiki and other extensions.